Different types of DC power supplies and converters are known in the state of the art. Most of these exhibit power losses and many have certain drawbacks. For example transformers, which are often used in such power supplies and converters for isolation and/or AC input voltage transformation, cause electromagnetic interference (EMI), power losses, bigger size, higher mass, and higher cost. Disadvantages experienced when using the known power supplies and converters include those caused by: the systematic power losses because of the use of rectifiers (or diodes); the presence of EMI, particularly because of ringing during switching; the particular operational envelope used, leading to power losses; and inadequate isolation between the input and the output. Furthermore, depending on the particular type of supply/converter used, there may be limitations on the input source voltage range and type (DC or AC), the output voltage range and the polarities of the input and output.